Web Resources
The National Council of Teachers of Mathematics offers a wide range of publications and Web sites with resources for teachers, including problems. Some materials are available free and others require NCTM membership -- www.nctm.org.

Figure This is a source of problems designed for use by families, many of which are also appropriate for classroom use. The site is aimed primarily at middle school-age students, but some problems work for higher or lower grades -- www.figurethis.org.

The Math Forum at Drexel University, mathforum.org/, has rich resources in all aspects of mathematics and mathematics education. Some parts of the site are subscription-based, but it is fully searchable. Specific problem resources can be found in Ask Dr. Math Problem sets (mathforum.org/dr.math/faq/) and the Problems of the Week section (mathforum.org/pow/other.html). The Math Forum also maintains a list of publications, including Web sites, with materials appropriate for term paper topics.

Eric Weisstein's World of Mathematics,mathworld.wolfram.com, is a free resource covering all areas of mathematics. It provides thorough explanations and definitions, often at an advanced level.